Kamen Rider x Kamen Rider x Kamen Rider: Ex-Aid, Decade, and Lupin!
by Time-Space lord Eon
Summary: Join James from Ex-Aid's Adventure and new character Matthias Redwall as they aid Rookie Rider Lupin in Time-Space lord Eon's first rider team-up!


**Alright, it's me Eon here. Some of my readers may recall that I said I would start a secondary story to run alongside** _ **Ex-Aid's Awakening**_ **, well this is an introduction to it before I post the story proper, I'll explain more at the bottom, so until then, enjoy!**

* * *

 ** _Kamen Rider X Kamen Rider X Kamen Rider_**

 ** _Ex-Aid, Decade, and Lupin_**

 ** _The first great team-up!_**

May 10, 2016, World of Lupin.

"Why did you drag me away from my home again?" James asked his companion. The man in question was a caucasian man of average height and above average fitness. He wore a simple grey T-shirt and jeans.

"Because you're the only Ex-Aid I know." the man walking beside him said as if it was obvious.

"Except, I've never met-" He cut himself of as he realized something, "You've met a future me haven't you."

"Yep."

The two came to a small back alley cafe called LeBlanc. "だから紳士、それは何だろう？" the owner asked.

"僕たちが2000円で得ることのできる最も充実したもの。" James's new friend responded.

"Ok, so they speak Japanese here." James observed as they were served a plate of curry and a cup of coffee. Taking a sip of his drink, "So, my eventual friend, who are you and why did you need me?"

"I guess I should start with my name, I'm Matthias Redwall." he took bite of curry, he face lighting up with joy. "I need your help because of a little mistake I made." he said as if it were nothing.

"What mistake might that be?" James asked more than a little suspicious.

"I might have gotten a Roidmude infected with bugster." he said in a soft tone, gesturing to turn away from the man that served their food.

"You what!? How!?" asked in shock and amazement, nearly spilling his coffee in the process.

"Yeah, I won't go into detail as to the how, but we need to meet up with this world's Rider and take down the Bugmude." he smiled at his naming of the hybrid monster.

"Ok, that's all well and good except for one thing." James took another sip of his coffee.

"What's that?" Matthias asked, totally baffled by the grandmaster.

"I don't speak Japanese!" James nearly yelled.

"Oh," Matthias looked dumbfounded before seeming to remember something and reached into his pocket. "Here you go," he held out what looked like a black earpiece.

"What's this, a universal translator?" he guessed based on Matthias's perfect Japanese earlier.

"Not quite, it will only let you understand the language spoken by a world's Rider." Matthias explained.

"I see," James answered. He didn't have the slightest clue how that worked, but he supposed he would have to trust the guy who whisked him away to another world while his wife was attending a baby shower.

" _This just in, reports are coming of a monster attack in Shibuya. It would appear that the Vigilante known as Lupin is currently fighting the monster. There are no reports of the vigilante Drive being on the scene at this time."_ The news channel on the cafe's tv caught the pair's attention for the first time.

"Looks like our cue, let's go give Lupin a hand." Matthias said like it was just time to go back to work after lunch.

* * *

"Damn it!" Lupin cursed as he was thrown back by the Roidmude. This one, 016, wasn't even an advanced Roidmude so why was it this strong?

The Roidmude chuckled at Lupin as he tried to get back on his feet. "It's no use trying to beat me, I've surpassed an advanced Roidmude without even changing form!" it laughed maniacally as he prepared to finish off Lupin when he heard the sound of motorcycles coming from behind. He looked and saw a pair of humans riding his way, and activated a density shift.

James and Matthias felt their bodies grow heavy as everything slowed down. The floated in the air for a moment before small objects that resembled bikes flew into their pockets and their movement returned to normal.

"What!? How!?" Roidmude 016 demanded as the two parked their bikes.

Matthias chuckled as he took his Signal Decader from his pocket. "This little guy works just like a shift car; I've got dozens of 'um!" he taunted as James went over to the wounded Lupin to hand him an elixir.

"Here, drink this." James said in a soft, kind voice.

Lupin hesitated for a moment, "Ok, doesn't seem like I have a choice," he took the elixir and his helmet dissolved. His short, frizzy hair falling down, weighted by his sweat, and covering his eyes. He lifted the blue glass bottle to his lips and downed the contents.

Reinvigorated, he leapt to his feet as his helmet reappeared. "Amazing! I feel good as new! We're not even in the Metaverse either!"

"Alright, let's take him out!" Matthias commanded as he produced a white device and afixed it to his waist, James following suit with his Gamer Driver.

"Who the hell are you!?" 016 yelled at the newcomers.

"I'm just a passing through Kamen Rider, remember that." Matthias cooly answered as he raised a magenta colored card.

"And I'm the guy who will change your fate, with my own hands!" James enjoyed the chance to use a more malevolent twist on Ex-Aid's catchphrase.

"Henshin!"

 **Mighty Action X!**

"Dai henshin!"

 **Kamen Ride: Decade!**

 _ **Gachan! Level Up! Mighty Jump! Mighty Kick! Mighty, Mighty Action X!**_

The energy screen moved over James to him transform into Ex-Aid level 2.

Matthias was surrounded by grey illusions of his rider form as card-like plates floated above his head. He smirked as the illusions overlapped over his body. The plates came down and merged into his helmet, causing his visor to flash green as his sides turned Magenta.

"A pair of pink riders?" Lupin questioned aloud.

"It's magenta!" Matthias shouted back. "Any way, the name's Decade." the magenta rider introduced.

"I'm Ex-Aid." the pink rider added absentmindedly, as he observed their opponent. Unfortunately, there wasn't much tactical advantage to be found at the Shibuya crossing. He did however have a large, three-dimensional area to work with.

"Decade, you maintain air superiority. Use Jack Form." he gave a simple instruction.

Decade slotted a card into his belt and activated it.

 **Kamen Ride: Blade!**

A screen of energy appeared and passed over Decade, transforming him into a blue Rider themed after a spade.

He slotted another card into his belt, which was unchanged, and activated it.

 **Form Ride: Blade Jack!**

The white portions on his helmet and torso turned gold. A set of wings appeared from his back.

He flew to the sky above the crossing and drew his gun, ready for action.

Ex-Aid turned to Lupin, "Get behind him and wait for my signal." Lupin nodded and ran off to one side.

Ex-Aid charged the Roidmude, who in turn charged at Ex-Aid.

As the two came together and started to brawl, Kamen Rider Drive drove to join the fight. "Hey, Belt, You know who that pink guy is?" he asked aloud.

"No clue." his belt responded.

Drive seemed perplexed for a moment, before he shrugged and prepared to join the fight. Just as he was about to take the first step, his toes were nearly removed by a falling playing card. He looked up to see Decade shaking his head. "Okay?" Drive stepped back, understanding the message.

Ex-Aid continued to brawl with 016, throwing a punch at the Roidmude's face. His face widened in shock as the android dodged and grabbed his fist. The shock changed to a smirk as Ex-Aid punched the Roidmude, freeing his hand and grabbed his opponent's arm instead. "Now!" he signaled.

 **Mighty Critical Strike!**

 **Final Attack Ride: Bl-Bl-Bl-Blade!**

 **Ultimate Lupin Stlash!**

Ex-Aid's hand began to glow with hot pink energy as he landed a punch into the Roidmude's stomach. Decade's leg began to spark with electricity as he came down on the Roidmude with a flying kick. The Lupin Blade extended to several times its length as Lupin went for the back.

In a single moment, all three attack where repelled. In the half-second before the finishers landed, the Roidmude changed shape. It was surrounded by the dark particles common for Roidmude shapeshifting, but these were accompanied by the bright orange Bugster virus.

In an instant, the newly-created Bugmude countered Ex-Aid's punch, and redirected Decade's kick, causing him and Lupin to hit each other.

016's new form had a silver body with red armor. Its head had two long protrusions which, with his stringy tail, produced a resemblance to a mouse.

"So, he's turned into Gatton." Ex-Aid observed as he returned to his feet.

"Huh, so this my full power." Gatton 016 mused as he inspected his new body. He looked to the riders, "I don't even need to beat you myself!" he called out as lesser bugsters began to appear. "Sayonara!" he called out as he broke down into bugster and escaped via the telephone line.

"Lupin! Follow him, we'll take out the mooks!" Ex-Aid ordered.

Before Lupin left, Decade threw him a disposable cell phone. "Use it when you find it." he explained. Lupin merely nodded before he ran off into the city.

 **Tire Koukan! Midnight Shadow**

 **Sh-Sh-Shadow!**

Drive, now sporting a purple tire, leapt into the battle as two clones appeared. "You know that I could have joined in earlier, right?" He questioned as he began to push several groups of bugster together.

"Hey, we had a plan and you weren't part of it." Decade, who had returned to his normal form, commented as he wiped out any nearby bugsters with ease.

"Sorry, it was already a risk to cram the three of us the close using our finishers. I was worried that it would backfire with one more." Ex-Aid answered as he bashed bugster with his hammer.

"Well, it backfired anyway." Drive commented back as his clones disappeared.

Decade noticed his phone buzzing a saw a text from Lupin. "Guys, the Roidmude's been spotted in Shinjuku! Let's finish this," he called out.

"Alright." Drive responded as he switched shift cars.

 **Drive! Type: Speed!**

"Hey, Decade, wanna do the coolest rider kick?" Ex-Aid asked as he prepared a red gashat.

 **Full Throttle Drive!**

"Dai Henshin." he called softly as he switched gashats.

 _ **Gachan! Level Up! Tri! Tri! Tri! Tridoron de Bakusou! Hitoppashiri Tsukeyo! Full Throttle Drive!**_

He transformed into a mix of his normal level 2 form and Drive. The main body turned black while the lines turned into Drive's signature red. His helmet resembled Dive's stuffed to fit in the chin of his normal form.

Decade pulled out another card and activated it with his belt.

 **Kamen Ride: Drive!**

Decade transformed into a near perfect duplicate of Drive's Type Speed form.

"Anyway, let's finish these guys." Drive said as he turned the key on the Drive Driver.

 **Hissatsu! Full Throttle: Speed!**

 **Final Attack Ride: Dr-Dr-Dr-Drive!**

 **Full Throttle Critical Strike!**

All of a sudden, Drive's car started up on his own. It began to spin around the the bugsters as the Riders' legs glowed red. As the Tridoron raced around in circles, the three riders leapt into the circle and jumped off of the Tridoron repeatedly, each pass landing a hit on the bugsters.

After several repetitions, all three riders launched into the center. After passing through the mob, all three riders touched down. The moment the riders rested on the ground, the bugsters all exploded simultaneously.

"Drive, can you cleanup everything here for us?" Decade asked, referring to collateral damage as well as quickly approaching police.

"Fine," Drive sighed.

Decade slotted a card into his belt.

 **Kamen Ride: Kabuto!**

 **Attack Ride: Clock-Up!**

As he started to move at near-light speeds, he picked up Ex-Aid and sprinted to Shinjuku.

* * *

When they arrived, the first thing Ex-Aid saw was that Lupin was watching from the high-ground. He smiled as he saw the options that the large buildings all around them afforded.

"Decade, I have an idea." he then whispered his plan into the Kabuto lookalike.

"Ah, good plan." Decade responded as he slotted a card.

 **Attack Ride: Clock-Up!**

Decade disappeared as he moved at super speed.

"Hey, ugly!" Ex-Aid called out to the bugmude, who, up until that moment either hadn't noticed the riders or was ignoring them.

"Who?," the monster questioned before turning around to see Ex-aid. "Oh," Gatton bemoaned as it raised it's giant battle arm.

Ex-Aid activated a pair of gashats.

 **Mighty Action X! Gekitotsu Robots!**

"Dai Dai Dai Henshin!"

He inserted both gashats and opened the lever.

 _ **Gachan! Level Up! Mighty Jump! Mighty Kick! Mighty, Mighty Action X!**_

 _ **A Gacha! Buttobase! Totsugeki! Gekitotsu Punch! Gekitotsu Robots!**_

Two energy screens appeared from the Gamer Driver, the one that normally appears when he transforms into level 2, and a second, red one that became a background for the pink one.

As the energy screens pass over Ex-Aid a small, red robot appeared and flew around Ex-Aid for a few seconds until it broke apart. The pieces from a red chest plate and a red headpiece over his helmet. The most notable addition however, was a massive robot hand similar to Gatton's.

Ex-Aid smashed a nearby brick block as he charged towards Gatton.

 _ **Kōtetsu-ka!**_

Ex-Aid's body turned into a reflective metal as he rammed his robot arm into Gatton's torso.

"Damn it!" Gatton yelled out as it's body began to crack as it was thrown through the air and land hard on the ground. Before Gatton could pull itself off the ground used his robot arm to slam its head into the ground.

Ex-Aid than used his free hand to lift Gatton into the air, dropping it for only a second to activate his finisher.

 _ **Gekitotsu Critical Strike!**_

Before Gatton hit the ground, it was pounded with another punch. The moment the punch connected, the robot fist launched off of Ex-Aid's arm like a rocket. As Gatton was pulled along, it saw Ex-Aid running at it at seemingly impossible speeds. It only took Ex-Aid a couple seconds to catch up, and when he did, he slammed his arm into the rocket. The moment the robot arm was reattached, Gatton felt another heavy hit as Ex-Aid fell behind.

As flew and bounced against the pavement, it wondered if it was even still in Shinjuku. Then it heard a sound that filled its core with dread.

 **Final Attack Ride: D-D-D-Decade!**

Gatton didn't see what hit it, but it felt a sharp pain in its back its armor broke away, returning to its original form.

016 struggled to get back on its feet as it looked for an escape route as the two riders began to close in. It found one in the form of a nearby alley, not bothering to think about what might be in there, the Roidmude dashed towards the alleyway. As soon as it turned the corner, it froze in fear when it saw a golden rider waiting. Every Roidmude knew of Lupin, the first to kill one of them, while 016 knocked him around like a toy earlier, that was before it received such heavy damage. Now, it could only hope it still had enough strength to win.

* * *

Lupin looked on in surprise as the Roidmude's now coreless body collapsed. It had been so strong before, but now it only took one shot. He had to wonder just who strong those other riders really were as they didn't seem to put any effort into the fight at all. As he considered this, he didn't notice the two in question.

"Holy crap, you took him out in one shot!" Lupin was snapped out of his thoughts by the unexpected voices. He saw Decade looking over the Roidmude's corpse when Ex-Aid spoke.

"Uh, do you mind if I take this? I know some who would love to have something like this," Ex-Aid asked casually pointing at the remains.

The request definitely threw Lupin for a loop. "Uh, of course," Lupin replied, unintentionally switching into his public persona. He almost chuckled when he realised the wording of his thoughts, but restrained himself from doing so.

As if on command, a silvery veil appeared on the ground, the Roidmude falling through and landing on something with a hollow thud. "Huh, guess it landed in the cellar," Ex-Aid noted. He then stood and turned to Decade, "We finished what we came here for, right?" he asked his magenta companion.

"Yeah, we don't have any reason to stay." Decade confirmed as he sat down, leaning on one of the alley walls. Another veil like the one the took away the Roidmude appeared next to the riders and Ex-Aid began to take his leave.

Before he could step through however, Lupin on pure impulse called out, "Wait" it was soft but commanding, and Ex-Aid heard. "Why do you have to go? You're so strong that the two of you could probably take out the Roidmudes in less than a month."

Ex-Aid let out a sigh before removing his belt, causing his armor to fade away. "Because," James said, "we have our own battles to fight, and besides, I have total faith that in time, you'll become just as, if not stronger than us." He responded in a soft, friendly tone.

"Yeah, and it's not like you _never_ see us again," Decade removed his own belt and returned to normal. "If ever you need more power than you can find in this world, I'll show up and lend you a hand." He looked at Lupin for a few seconds, as if he was waiting for something. "C'mon, aren't going to take off your armor too?" he asked in a tone that reminded Lupin of Ryuji.

"Oh, right." Lupin's jeweled armor gave way to a black school uniform. Lupin himself was about average height for a Japanese person his age, which made feel tiny next to the other riders. His other noteworthy feature was his black, frizzy hair. "My name is Ichijo Kira!," he bowed reflexively to his seniors.

"Well, Mr. Kira, it was nice to meet you, but I should be going," James returned the bow before stepping back into the veil.

"Same," was all Matthias said before he fell through another veil on the ground, leaving Ichijo alone. At least, until a black cat turned in the alley and jumped up into his bag.

"Hey, Morgana," Ichijo greeted the cat.

"Hey, yourself! Do you know how hard it was to get this far from the station!?" Morgana meowed back in annoyance. "Anyway, how did you beat that super strong Roidmude?" he inquired as he settled into the bag.

"I had help," Ichijo replied simply as he started to make his way home.

 _ **Mission Complete!**_

* * *

 **Alright, how did you guys feel about that. I guess to start with, I'll talk about the new characters, starting with Matthias. First off, 50 points to however can recognize the reference in his name. While I do have an idea for his story, for the time being he'll be a team-up only character, and yes after these first two, I plan to write more rider stories which might get tema-ups for a while and those are going to be when he shows up. As Ichijo and Drive? You'll get to learn about them in their story. Also as for continuity involving James, this story is set in between chapters 11 & 12, so there maybe some reference to this later down the line. I guess to finish off, I'll explain why I wrote this in the first place. After i announced the second story, I realized it would take longer than expected to write, so I decided to do something special first, hence this. However, I started this around the beginning of the school year, which lead me to more or less forget this for a while. But rest assure you, I **_**will**_ **have at least two chapters of Ichijo's story up before new years. Speaking of, I'm Time-Space lord Eon hope that you will all join me for…**

 _ **Kamen Rider Lupin: Phantom Joker**_


End file.
